Yes, use your favorite text-editor to create a custom file containing all the items you want to add. Copy the file to your phones external memory card according to the following format:
Example can be found at the bottom of this post. Lets have a closer look at apple.
Carbs/100 gram: 8.2
Protein/100 gram: 0.2
Fat/ 100 gram: 0
Alcohol/ 100 gram:0
grams per serving: 1 (if you are not sure what serving size to use, just type 1, and specify “gram” as the unit to use.
GI-Value: 38 (If you do not know the GI-value for the specified item, use “-1”
Do not forget that each line must end with a “,”
Apple,8.2,0.2,0,0,1,gram,38, Avocado,0.8,2.6,19.4,0,1,gram,-1, Banana,18.3,1.1,0.4,0,1,gram,52,